| Sendt: 14 April 2006 kl. 10:18 | IP-adresse registreret
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Jeg har en ældre Denon PRA 1000, en udmærkedet forforstærker. Jeg faldt over en tråd på nettet som omtaler at skifte nogle upamps i den. Jeg kunne godt tænkte mig at høre nogle kyndige om de forslået Burbrown-kredse er det bedste, og måske har DU et andet forslag baseret på erfaring. Jeg bruger slet ikke RIAAen så det er kun liniedelen som jeg vil rører ved. Der står:
Re: Any tweaks for Denon PRA-1000 or POA-1500 - nightdoggy 08:59:23 03/14/06 (5)
The PRA-1000 is an excellent pre with a large toroidal transformer, Noble volume pot., unusual blue epoxy pc boards and a superb mc phono. I completely rebuilt mine. It is a dc servo design with feedback op amps used in the mc, mm and line stages. I changed the 741's (bad) op amps (2), (mc stage) to Linear Technology LT1115's. It is the lowest noise op amp available. I changed the 4560 (1) in the mm section to Burr-Brown 2132. I changed the 4558 (1, like a dual 741) in the line stage to 2132. I replaced every single electrolytic with matched Panasonic FA ones. I replaced every single carbon film resistor to matched (L-R) 1% low-noise metal films. I bypassed the balance control. I replaced and added heat sinks to the power supply regulators. They run very hot-discolored the board. Lastly, ultrasonic pcb wash, silver teflon wire and calibration. The service manual is essential. The results were amazing. There is zero noise whatsoever open circuit mc phono. Much work but worth it.
Hvad tror du du er bedst?
Mvh
Brad __________________ NSR/Gianelli - two stroke retro
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